Rashi: If a man is a stranger, and veers from the Mitzvah, his way is wayward.

R. Yonah: "Derech Ish" is a man's Midos. Man's nature and Midos are contrary and foreign. Even though bad Midos are in him, they are foreign to him. He sees them in someone else, and despises them. The intellectual Nefesh does not draw them close. They are like strangers. Even though he sees them constantly, the entire day, in himself, desire overpowers and he does not see the detriment of the bad Midos in himself. His sin is great for this - he sees bad Midos in others, and does not take Musar for himself.

Malbim: This explains "Shod Resha'im Yegorem Ki Me'anu La'asos Mishpat" (7). Man's nature is to go in the way of Mishpat, not steal, and love Emes and Tzedek. This enables civil conduct. However, these Resha'im, and Ba'alei Leshon ha'Ra who were mentioned, are the opposite of man's nature. They distance from Mishpat to plunder, from Emes to Sheker. The straight path is foreign to them. They fear being plundered, for the entire society opposes them. Their path is reversed and foreign.

R. Yonah: If the Derech and Midos are clear, his action is straight. One must strive to put to his heart to fix his Midos and purify his heart. Then he will attain all attributes of Midos and actions, for Midos guide actions. Even though bad Midos seem clear to one who has them, they do not ¹ when he sees them in others. However, a total Rasha who accustomed his Nefesh to Aveiros and robbery, and his deeds lean to Sheker, sin and deception, his Nefesh's eyes are plastered from seeing Chachmah. Bad Midos are pleasant to them, and they despise good Midos - "Anshei Damim Yisne'u Sam", "v'So'avas Rasha Yeshar Darech" (29:10, 27).

Malbim: Zach is clean of Pesoles (waste). It is proper to say so about cleanliness from desires in practical Sechel. Yashar is in investigative Sechel. Zach is in Chachmah, and Yashar is in Binah. One who is not Zach in his Midos, he sins against the laws of Chachmah. He cannot be Yashar, for desire tilts him from the straight path to the opposite - Hafachpach. If he is Zach, he goes straight; the nature of Binah agrees with straightness.